When a mobile terminal performs handover in a broadband wireless access system, the mobile terminal performs the handover for all frequency regions regardless of subcarrier allocation scheme. To perform handover, first, the mobile terminal receives information of neighboring base stations from a current serving base station. The mobile terminal then requests that handover to a neighboring base station be performed when it is determined based on the received neighboring base station information that the neighboring base station provides a higher signal or service quality than the current serving base station.
A mobile terminal, which is transmitting and receiving data using a specific band, also switches to a normal mode in which subcarriers are allocated to all frequency regions before and after handover is performed. After the handover is performed, the mobile terminal requests switching to a data transmission/reception mode or the base station switches the mobile terminal from the normal mode to a mode, in which data is transmitted and received using only a specific band, based on channel status information transmitted from the mobile terminal.
A mobile terminal located at a cell boundary frequently performs handover. Especially, a mobile terminal which transmits and receives data using only a specific band among those located at cell boundaries will frequently switch, after handover is performed, from the normal mode to a mode in which only the specific band is used to transmit and receive data more than a number of times corresponding to the number of handovers. This causes problems in that power of the mobile terminal is wasted and resources are used inefficiently.